Consider the unbalanced reaction: p4 (s) + f2 (g) → pf3 (g) what mass of fluorine gas is needed to produce 120. g of pf3 if the reaction has a 78.1 % yield?

Answer is: 99.25 grams of fluorine gas is needed.

Balanced chemical reaction: P₄ (s) + 6F₂ (g) → 4PF₃ (g).

m(PF₃) = 120.0 g; mass of phosphorus trifluoride.

n(PF₃) = m(PF₃) ÷ M(PF₃).

n(PF₃) = 120 g ÷ 88 g/mol.

n(PF₃) = 1.36 mol.

From chemical reaction: n(PF₃) : n(F₂) = 4 : 6 (2 : 3).

n(F₂) = 1.36 mol · 3 / 2.

n(F₂) = 2.04 mol; amount of substance.

m(F₂) = n(F₂) · M(F₂).

m(F₂) = 2.04 mol · 38 g/mol.

m(F₂) = 77.52 g ÷ 0.781.

m(F₂) = 99.25 g.

plasma is the state of matter where the substance is ionized and has no definite shape or volume. the fact of being ionized makes the substance a good electrical conductor.